To improve the stability of the magnet-girder assemblies in the ESRF storage ring, vibration investigations have been carried out for in situ magnet-girder assemblies and a prototype. Characterisation tests were performed : operating response measurements, static stiffness measurements, modal testing. A finite element modelling (FEM) is being carried out for the prototype assembly. First result...

In this paper we present a simple, yet powerful, method for the identification of stiffness matrices of structural and mechanical systems from information about some of their measured natural frequencies and corresponding mode shapes of vibration. The method is computationally efficient and is shown to perform remarkably well in the presence of measurement errors in the mode shapes of vibration...

We report high-precision absolute distance and vibration measurements performed with frequency scanned interferometry using a pair of single-mode optical fibers. Absolute distance was determined by counting the interference fringes produced while scanning the laser frequency. A high-finesse Fabry-Perot interferometer was used to determine frequency changes during scanning. Two multiple-distance...

We propose a novel sensor system for monitoring the structural health of a building. The system optically measures the relative-story displacement during earthquakes for detecting any deformations of building elements. The sensor unit is composed of three position sensitive detectors (PSDs) and lenses capable of measuring the relative-story displacement precisely, even if the PSD unit was incli...

BACKGROUND CONTEXT People with neck pain display a diminished joint position sense and disturbed postural control, which is thought to be a result of impaired somatosensory afferent activity and/or integration. Afferent processing can be artificially manipulated by vibration and was shown to reduce motor performance in healthy subjects. However, the effect of vibration on sensorimotor function ...

In this paper, we report high-precision absolute distance and vibration measurements performed with frequency scanned interferometry using a pair of single-mode optical fibers. Absolute distance was determined by counting the interference fringes produced while scanning the laser frequency. A high-finesse Fabry-Perot interferometer was used to determine frequency changes during scanning. Two mu...

Many vibration-exposed workers have been found to suffer from muscle fatigue and decreased grip strength. Therefore in order to quantify and determine safe levels of human exposure to vibration, measurements and analysis of significance vibration factors are necessary. There are three main objectives in this study. The first one is to investigate the characteristics of vibration factors (vibrat...

Based on the development of numerical analysis techniques over the past decade, the engineer can easily model the internal flow conditions and vibration characteristics of turbomachinery. When focusing on vibration response of rotating blades, it is easy to predict the resonance frequency; however difficulty remains in the prediction of vibrational stress. The primary reasons include: The unste...